In your wordpress admin screen, Simple Banner should be in the left sidebar.
I cannot seem to find it there.
I would make sure you did activate it first and then clear your browser cache just in case. Sign out and sign back in. It should be visible to admins in the admin page. If you’re signing in as a lower role than admin you may not be able to see it.
I have done that and still can’t seem to find it. I believe that I am an admin. I can edit everything else.
If you’re in the WordPress Dashboard and Simple Banner has been activated from the plugins page and you still don’t see it in the sidebar then you most likely are not signed in as an admin role.